The invention provides an engineering escherichia coli capable of efficiently producing hyaluronic acid (HA) and a preparation method thereof. The engineering escherichia coli is obtained by transferring escherichia coli through constructing recombinant expression vector commonly expressed in escherichia coli by gene Has containing HA synthetase and gene containing uridine diphosphate glucose phosphate dehydrogenate. The engineering escherichia coli capable of efficiently producing HA, provided by the invention, is pHK/JM109 with CGMCC No.3926. The engineering escherichia coli provided by the invention can produce 29-2.5g/L of HA. Compared with the yield in the prior art, the highest yield of HA obtained from gene spHas synthesized by Gram positive strep HA which is expressed in escherichia coli is enhanced by about more than 10 times.